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Skipping at slow acceleration

My 1992 Dodge W150 truck skips when I am accelerating slowly from a stopped position. It is an automatic and seems to change gears properly. It skips between every gear change until you reach cruising speed. The skip does not occur or I do not notice it, if I accelerate rapidly. After I bought it, a mechanic installed new plugs, plug wires, coil, rotor, dist cap, fuel filter and speed sensor. Truck has over 90,000 miles. Can anyone give me any suggestions. Thanks.

Try cleaning the MAF (mass air flow) sensor, if it has one.

The things your mechanic did make sense for the symptoms you report. At least that part of your routine maintance is up to date. But there’s still a problem. hmmm … Ok, Anything affecting the air/fuel ratio can also cause this. Leaking vacuum hoses, vacuum devices, the MAF as mentioned above. Also a faulty EGR should be considered since it happens on acceleration, which is when the EGR is activated. Clogged fuel injectors or faulty fuel pressure are possible but less likely. Verifying that the PCV valve is working is easy to do and you might as well have it done as there’s a slight possibility this is the problem. Another fairly easy thing to have done is a compression and leakdown test. Again, this is unlikely to identify the cause, but is fairly inexpensive and you might get lucky.

Thanks for the advice. I will try these things and let you know the results.

Just letting everyone know that sawyer and sawman are one and the same. I forgot my username and had to create a new account.

I have an 85 Cutlass Ciera that was having the same symptoms you described. I took it to several mechanics and non of them could figure it out. They suggested replacing all sorts of parts, tune up this, fuel additives that, this test, that test etc. All I could see was dollar signs and not for me, but for all of these so called specialists. Then one day I was talking with a co-worker about the problem. He used to be a service adviser at a Chevy dealership before joining the Navy. He immediately blurted out “It’s your throttle position sensor”. Of course, I thought that he was insane but took his advice and changed it out, problem solved!! So, if all of the parts that were changed that you mentioned and there is still a problem you may want to look into the throttle position sensor. It is a part that is sometimes overlooked when trying to diagnose acceleration problems. I believe you may even be able to check it with an ohm meter to verify if it is bad. For me, it was a cheap fix (around $25.00 and 15 minutes of my time to fix it) and certainly didn’t involve all of the expensive part replacement and zero result approach that others were suggesting.

Sawyer:

With the vehicle running in a safe location like an empty lot.

While pressing on the brake shift into gear, continue to keep pressure on brake while giving just a slight amount of pressure on the gas peddle.

What you are trying to do is simulate a light load to feel if the engine misses.

My guess is that you are actually experiancing is 1st, 2nd, 3rd gear clutch pack shutter.

I recommend tracking down a highly trusted and reliable shop to check out the transmission.

It may be nothing more than a case of replacing the fluid and filter.

Late model Mopar Transmissions are famous for this.

Just letting everyone know installing a new EGR valve has seemed to solve the problem. When I removed the old one, someone had placed a “dime” in the center opening of the old EGR valve. It was a South Carolina truck and they do not have emissions test there. I don’t know if stopping the EGR opening is a way to try to get more power or what, but truck is now running better than it ever has since I bought it. Thanks again for all the helpful suggestions.