# Toyota T100 starts rough when warm, now idles rough **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** cylinder, transmissions, engines, toyota, manual-transmissions\ **Created:** [May 1, 2010, 3:38am UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177 "2010-05-01T03:38:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![bardiferous](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bardiferous/32/780_2.png) [@bardiferous](https://community.cartalk.com/u/bardiferous)\ **Post date:** [May 1, 2010, 3:38am UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177/1 "2010-05-01T03:38:23Z")
For quite some time (years) my 1995 T100 (base model 4 cyl 2WD manual tranny) has started easily when cold but gets cantankerous when starting warm (or hot engine). The check engine light would intermittently come on and go out on a weekly to monthly basis, but has not come on in 3-4 months. A friend has played around with the EGR valve, and the problem has gotten worse. Tonight, it was running a bit rough even after startup. Have a new rotor/distributor cap, plugs & wires are relatively new, air cleaner is K&N and clean, vacuum hoses all seem good and well-connected, PCV valve is clean. Mileage is a bit lower but not drastically lower. I’m thinking, just replace the EGR valve. But could it be something else? What could it be? ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [May 1, 2010, 12:46pm UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177/2 "2010-05-01T12:46:05Z")
First clean your MAF sensor (if so equipped) and if that helps you should either ditch the K&N or at least get the oil level down. Over-oiled K&Ns notoriously create intake issues. Nothing that you said has been done or inspected involved fuel supply. Put a fuel pressure gauge on it to investigate. Leave it on for a while to see what the pressure does on warm shut down. My first guesses about your actual problem involve either a bad check valve at the fuel pump (too little fuel on restart) or a leaking fuel pressure or injector (leaking fuel into the intake). How old is the fuel filter? Without knowing either the error codes associated w/ the check engine light or what about the EGR was messed with it would be hard to comment. However, if your EGR were stuck open it could behave like this - it basically acts like a vacuum leak. I think you have a fuel problem tho. ---
**Author:** ![bardiferous](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bardiferous/32/780_2.png) [@bardiferous](https://community.cartalk.com/u/bardiferous)\ **Post date:** [May 1, 2010, 4:13pm UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177/3 "2010-05-01T16:13:49Z")
My friend/mechanic will be doing a fuel pressure test next. He’s tried to clean the EGR valve with carb cleaner (yesterday) and it started & idled fine. Later, it began to idle roughly again and this morning it has varied from idling & running roughly to running & idling smoothly. BTW - truck is gently approaching 200K miles; 198,500 & counting! See pic from Feb storm (before the 2nd 30") ---
**Author:** ![Joe-Guy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joe-guy/32/124_2.png) [@Joe-Guy](https://community.cartalk.com/u/Joe-Guy)\ **Post date:** [May 1, 2010, 4:44pm UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177/4 "2010-05-01T16:44:33Z")
Nice looking truck! ---
**Author:** ![bardiferous](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bardiferous/32/780_2.png) [@bardiferous](https://community.cartalk.com/u/bardiferous)\ **Post date:** [May 3, 2010, 1:50pm UTC](https://community.cartalk.com/t/toyota-t100-starts-rough-when-warm-now-idles-rough/48177/5 "2010-05-03T13:50:02Z")
Thanks!