Hesitation under throttle

[997Sbeebe]

Before I purchase the general Maintenance Kit from Pelican, I thought I'd run my current scenario by you guys and see if anyone has other ideas on my issue. Recently purchased a new-to-me '87 3.2 and I have a general, near constant hesitation under throttle. I plan on replacing all the items in the Maint. Kit, but I also don't want to overlook something I'm not considering. Car has a smooth, stable idle and revs freely, but once under way, a general (pulsing like) hesitation is persistent. A handful of times, it has corrected itself and the car surges forward with much more power. In general though, it's as if there's a constant miss that pulls power in that pulsing manner. I'm obviously defaulting to cap/rotor/plugs/etc. and/or dirty fuel filter. Injectors and fuel pump also seem like logical possibilities, but I'll start with the smaller items first. Any other thoughts on what could be causing this condition - maybe a sensor? Any thoughts would be greatly appreciated. TIA.

[997Sbeebe]

one more question - is the Bosch WR7DC+ plug, included in the maintenance kit from Pelican, considered a preferable plug for the 3.2? i know sometimes there are better options than the ones included in general kits. thanks.

[T77911S]

you have to start with the things you mentioned. cap, rotor, plugs filters and maybe wires.
then go from there. check for air leaks. have a smoke test done.
O2 sensor. they are good for about 100k miles. replace if older.
run some techron thru it. i like to put a bottle in with no more than half a tank. then when i can, i will hold the RPM's hi when driving. like from llight to light. hold it at around 4500 rpm. you need steady hi rpm's.
then maybe run a tank of clean gas and the repeat.

AFM could have some issues if nothing else. but check for air leaks or just replace all the rubber on the engine that has vauum on it.

i never thouhgt this could happen but the CPS did cause my BMW to run bad. i would not believe except i saw it. just smonething to keep in mind. dont run out and buy one.

[997Sbeebe]

thanks for the reply, T77911S. the kit has already been ordered from Pelican - no harm in replacing all those components, no matter the issue.

[JAR0023]

Surging at constant throttle input sounds like the oxygen sensor. Simple enough to test. Unplug the sensor and go for a drive and see if the surging goes away.

Nothing wrong with the Bosch plug but there are plenty of NGK fans on this board, me among them. BPR6ES is the equivalent NGK plug and correct for the 3.2 Carrera. -J

[997Sbeebe]

thanks for the recommendations, guys. i doubt the parts will be here today, so i'll start by testing the O2 sensor this weekend. much appreciated.

[DRACO A5OG]

After that, just replace the fuel filter when you get the kit to see if it is fuel related then cap/rotor & plugs. Also you did order a spare DME relay, you need this in any case. Do not get the URO brand.

[cabmandone]

Putting this out there more as a question than answer to your question but, could it be the cylinder head temp sensor? Check to make sure it is plugged into the connector in the engine bay. When I say check, I mean push it on. I had mine get slightly knocked off and it looked ok but ran like crap.

BTW, it would bog down like it wasn't getting fuel then it would take off like it got a ton (which it was) then bog down again.

[997Sbeebe]

the CHT sensor certainly seems like a potential culprit, cab. thanks for the suggestion of checking the connection. i will do that as well. mine currently run rough more than good, but when it runs good, it surges with smooth power. need this rectified so i can enjoy the car.

[997Sbeebe]

JAR0023, it looks as if your suggestion was right. i unplugged the o2 sensor over the weekend and the car ran much better with smooth acceleration throughout the range. i pulled the o2 sensor and it looked awful. new one on order - to be installed with all the other parts above.

thanks again for all the suggestions.