I think the issue I'm having with my intermittent hesitation is my TPS, my question is are there any replacements to avoid brand wise? I don't mind paying for quality but if a cheaper replacement is just as good then i'll go that route. Thanks in advance guys, 89 5.0 TPI T/A

 

I have had good luck with the BWD EC1038P replacement I found at advance auto. It has worked without issue since and it has been a few years. I don’t know if it’s still around. Sometimes AC Delco has an actual GM replacement part so that may be worth a look too.

 

Thanks for the info Reddragon, I just ordered the AC Delco from Rockauto, neither Advance or Autozone had one in stock, figured I had to wait for it at either place so may as well get the AC Delco.

 

Did the old TPS voltage not go high enough or act erratic when testing?

Another thing to try is set it at like .61 instead of .54 on the MAF cars. I saw on a few threads how some guys felt it gave slightly crisper throttle response. I tried it and while not huge it did feel a touch better…might just be the placebo effect but I left it and the car has been running great.

 

It was erratic when moving the throttle slowly, numbers jumped all over the place.

 

Not sure if your issue is solved or not. If so, disregard. But if not, many don't realize that improperly operating/old injectors can cause hesitation, generally when going from idle to moving with mild throttle. This is especially true with factory Multecs even if they ohm out correctly cold and hot and noid lights show proper operation. Been there, done that.

 

Thanks for the tip, had injectors cleaned and serviced in 2019 although not being driven much doesn't help, however I haven't changed the TPS yet and car has been running pretty decent the more I run it. I did run a tankful of premium with seafoam in it and that has seemed to help so it very well could be the injectors.

 

"not being driven much doesn't help". Yes, with ethanol fuel, this can cause issues. Seafoam does a good job, but Chevron Techron specifically targets injectors. Search for reviews/results.

 

Not a Chevron even remotely close to me lol, I always run 93 or higher in it, but I'm gonna dump another can of Seafoam in it next fill up.

 

Meant this available at any auto parts store < $5:

 

Oh I see, I'll give it a shot next time, Thanks

 

So car is still not running right, hooked up to the scanner all parameters are within spec according to shop manual, even took it to a buddy of mine and hooked up to his and all looks good, So I finally bought a set of Bosch III injectors and will be installing them hopefully soon. From what I've read on here and other places the Multecs are garbage and it won't hurt to change out some old original injectors anyway. Other than the distributor this is the only thing left.

 

The Multics are trash, I would add up an adjustable FPR in case you have to adjust pressure for the Bosch 3s, some say they are a little lean so with the FPR you can add a little more fuel if needed.

I have had the Bosch 3s for a few years and they have been great, I run my pressure at 48psi and BLMs look pretty good too.

 

Those Multecs are sort of an oddball GM creation to avoid paying Bosch to use their design. Keep us posted on your results with the new injectors.

 

My fuel pressure as of now is 49 psi with the stock regulator, I just ordered new gaskets, egr, and regulator from Rockauto so I can get this job started, summer is half over and the car sits, makes me nervous in certain situations when needing to pull into traffic. Hopefully this will get it back on track to where I can enjoy the car again.

 

Well injectors are installed, wasn't too bad of a job, only issue I had was one of the plenum bolt hole threads were a little screwed up, had to go buy a tap to chase the threads, would have had it done yesterday if wasn't for that. Car is running 90% better than it was, still has an occasional hesitation but the more I drove it today the better it ran, just ordered a new Delco ICM, yeah still throwing parts at it lol, There still maybe some bad fuel in it, car hasn't had very many miles put on it in the last two years, it was definitely better pulling out into traffic, still made me nervous for a while but gradually got better throughout the day.

 

Car is fixed, it was a defective Accel ignition coil, runs like it should now, Finally!

 

That’s great to hear! Isn’t it funny how in terms of ignition parts the AC Delco stuff is better quality than the supposed performance upgrade parts?

 

Night and day difference, I've never had any luck with so called high performance ignition parts, I should have known it was that coil, but I thought " Nah it can't be that, it's relatively new " Well at least I learned a lot about working on these TPI cars anyway lol

 

So over the weekend I cleaned my MAF, checked and readjusted minimum idle, IAC, and TPS. My new IAC wasn't working right, wouldn't maintain a steady idle all the time, I cleaned and reinstalled the original IAC and cleared up that problem. Car is starting and running like new, running the best it ever has since I've owned it. I took the day off today and used it to run some errands, what a difference it makes when everything is working as it should, really loving this car again!

 

And these cars are really starting to draw attention too. Nice to drive something that's getting rare. Not good for robbing a bank though.