# 1978 Chrysler Aspen running rough **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chrysler, aspen\ **Created:** [June 15, 2018, 10:52pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291 "2018-06-15T22:52:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![DanielMcCarthy](https://avatars.discourse-cdn.com/v4/letter/d/3d9bf3/32.png) [@DanielMcCarthy](https://community.cartalk.com/u/DanielMcCarthy)\ **Post date:** [June 15, 2018, 10:52pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/1 "2018-06-15T22:52:06Z")
The 360 V8 still running pretty roughly. Put new two barrel, filters, plugs like a normal tuneup. Only 80,000 miles on the Cordoba chassis when come from Santa Fe. Had harsh idle since; don’t know why. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [June 15, 2018, 11:44pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/2 "2018-06-15T23:44:40Z")
Have you done a compression check to make sure all the cylinders are working as designed? ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [June 16, 2018, 12:37am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/3 "2018-06-16T00:37:39Z")
So you replaced the carb, and that didn’t fix it? hmmm … on my 302 Ford truck from the same era , whenever I get a rough idle, when it starts one day for no apparent reason after it has run fine for months, it is usually caused by a vacuum leak. Check all the vacuum hoses, and test all the vacuum operated devices with a vacuum pump to make sure they hold vacuum to 20 inches. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 16, 2018, 12:39am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/4 "2018-06-16T00:39:28Z")
Are you running ethanol gas in that old car? Tester ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [June 16, 2018, 12:45am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/5 "2018-06-16T00:45:39Z")
I have heard stories about non oem plugs causing problems. It could need carb adjustment, see if the choke opens all the way. ---
**Author:** ![DanielMcCarthy](https://avatars.discourse-cdn.com/v4/letter/d/3d9bf3/32.png) [@DanielMcCarthy](https://community.cartalk.com/u/DanielMcCarthy)\ **Post date:** [June 16, 2018, 1:26am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/6 "2018-06-16T01:26:45Z")
Don’t think so, just the Shell’s regular stuff. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 16, 2018, 1:31am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/7 "2018-06-16T01:31:09Z")
Look on the pump. Does it state 10-15% ethanol content? Tester ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [June 16, 2018, 11:47am UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/8 "2018-06-16T11:47:08Z")
> [@DanielMcCarthy](#): > > Shell’s regular stuff. Which virtually everywhere contains up to 10% ethanol. The car wasn’t designed to run on this stuff. The ethanol is eating away at the rubber parts in your car, including those fuel lines, pump and carb. It might not be your current problem - I like the vacuum leak idea - but it will cause problems for you down the road. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [June 16, 2018, 1:21pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/9 "2018-06-16T13:21:37Z")
> [@DanielMcCarthy](#): > > Don’t think so, just the Shell’s regular stuff. 🤨 ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [June 16, 2018, 2:46pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/10 "2018-06-16T14:46:41Z")
> [@Mustangman](#): > > The ethanol is eating away at the rubber parts in your car, including those fuel lines, pump and carb. Those are all replaceable. When I re-built my carb last year I bought hose in bulk and replaced all of them for $few. The manual for my '87 Toyota pickup warns about the dangers of methanol, not ethanol. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [June 16, 2018, 3:23pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/11 "2018-06-16T15:23:32Z")
For a short tutorial on ethanol in older cars; [https://www.hemmings.com/blog/2012/11/14/tech-101-ethanol-in-gasoline-and-its-effects-on-collector-cars/](https://www.hemmings.com/blog/2012/11/14/tech-101-ethanol-in-gasoline-and-its-effects-on-collector-cars/) In the article it sates you can replace rubber parts with ones more resistant to ethanol. I’d add - IF they exist! Likely a carb rebuild kit and possibly fuel pumps for a '78 Aspen do NOT exist. That just means carb rebuilding and fuel pump replacement will likely be a regular occurrence. > [@RandomTroll](#): > > The manual for my '87 Toyota pickup warns about the dangers of methanol, not ethanol. Since ethanol in fuel was not mandated until 2007 - a full 20 years after your Toyota’s manual was written - it was likely omitted because it was not yet an issue. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 16, 2018, 4:11pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/12 "2018-06-16T16:11:14Z")
Ethanol was mandated in Minnesota in 1992. Tester ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [June 16, 2018, 6:46pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/13 "2018-06-16T18:46:01Z")
> [@Mustangman](#): > > Since ethanol in fuel was not mandated until 2007 - a full 20 years after your Toyota’s manual was written - it was likely omitted because it was not yet an issue. Methanol has never been mandated; I’ve never seen it used as an additive by gasoline manufacturers. I used to use it (_Heet_) in winter to dry my gas but switched to isopropanol (_Iso-Heet_) when that came out. But ethanol has been used as an additive that long. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [June 16, 2018, 8:47pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/14 "2018-06-16T20:47:36Z")
> [@RandomTroll](#): > > Methanol has never been mandated No, it hasn’t been mandated, anywhere, anytime. MTBE was the additive used to reduce pollution until it was found to be a problem and eliminated. Methanol was used as racing fuel (at Indianapolis - now they use ethanol - and sprint car racing) for a very long time and was, and is, readily available. Toyota must have figured someone would try some in the tank and decided to tell their owners. You may have used Heet, but it is unlikely you added a gallon to 9 gallons of gasoline. Ethanol does attack nitrile rubber commonly used in older cars for fuel lines, fuel pump membranes and carburetor parts. The higher the percentage, the more aggressive the degradation. Your '87 truck will, at some point have problems from running modern gasoline. Stock up on fuel pumps, filters and carb rebuild kits if you plan on keeping this truck running. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 16, 2018, 8:57pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/15 "2018-06-16T20:57:03Z")
Ethanol also corrodes the metal components of the fuel system. ![](https://global.discourse-cdn.com/cartalk/original/2X/a/ab5de84a69502f7d31483f6e46f6308d97150f33.jpg) That’s why we have gas that contains no ethanol in Minnesota. Tester ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [June 16, 2018, 10:37pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/16 "2018-06-16T22:37:35Z")
Some areas have been using E10 since the late 1980’s as a winter fuel to reduce local pollution trapped by the inversion layer. I suspect that the supply of fuel hose changed years ago to be compatible with common fuels. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [June 16, 2018, 10:59pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/17 "2018-06-16T22:59:39Z")
Plug wires new? Compression tested? ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [June 16, 2018, 11:28pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/18 "2018-06-16T23:28:47Z")
Why was the carb replaced? To address this harsh idle symptom? If so , it is possible the replacement carb hasn’t yet been set up properly. It’s generally not possible to simply bolt a replacement carb on the intake and be done with it. There’s some further adjustments needed to tune the carb to the engine. Incorrect/unbalanced idle mixture adjustment, etc. And of course it’s possible the replacement carb has a problem too. Did the carb paperwork mention anything about “flow testing”? Is the harsh idle occurring on both a cold and warm engine? Worse on one vs the other? How does it perform at higher rpms during normal driving? What’s the cold and warm idle rpms? ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [June 17, 2018, 2:32pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/19 "2018-06-17T14:32:21Z")
> [@Mustangman](#): > > Methanol was used as racing fuel Not in pickup trucks. Some fleets use pure methanol. Nobel-prize-winning chemist George Olah thinks it’s the fuel of the future. > [@Mustangman](#): > > You may have used Heet, but it is unlikely you added a gallon to 9 gallons of gasoline. I definitely did, 12 ounces to 15 gallons. > [@Mustangman](#): > > Your '87 truck will, at some point have problems from running modern gasoline. Stock up on fuel pumps, filters and carb rebuild kits if you plan on keeping this truck running. Last year AutoZone had a rebuild kit in stock, as well as all the other stuff: I don’t need to stock up. Compression is still book; emissions are still book. It runs as well as new. I re-built the carb at 30 years. Other than a leaky accelerator pump, it looked good. I replaced all the hoses because it was cheap and I had everything apart. The old hoses look good. > [@Tester](#): > > Ethanol also corrodes the metal components of the fuel system. ? I find no sign of this in my pickup. > [@Tester](#): > > That’s why we have gas that contains no ethanol in Minnesota. You have it for the same reason you have everything else: people pay for it. You also have cigarettes, lite beer, and lutefisk. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [June 17, 2018, 3:16pm UTC](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291/20 "2018-06-17T15:16:05Z")
> [@RandomTroll](#): > > I definitely did, 12 ounces to 15 gallons. You definitely did not add 1 gallon to 9 per the statement above. Commercial gasoline is up to 10% ethanol, this is a 1.2% concentration > [@RandomTroll](#): > > Not in pickup trucks. Not a relevant comment. [Next page](https://community.cartalk.com/t/1978-chrysler-aspen-running-rough/119291.md?page=2)