ouch! summit sells the for 3 something i believe. also try the gm parts sponsors on this board, they do wonders on getting u a part cheaper than your local gm dealer.

 

clean the MAF i had to drive home at 4500 rpm cause the little sensors on it were dirty on time cleaned them and shazamm

 

how do you do this?

 

the least expensive and least time consuming is to test fuel psi running and driving.fuel pump jobs are not that difficult i do them in an hour 1/2....

 

I can vouch for junk optis, bought a replacement from a chain store, tried to start the car, nothing, bought a gm replacement, fired right up.

 

I would check the fuel pressure. Also might want to pull the vac line off the FPR and see if you smell gas.

 

do the fuel filter just to ssay you tried it cause its cheap.. if not that id be looking to the pcm or the fuel pump like they said... if its not the pump... pcm can cause all your problems but is by far the most expensive... its deff not the collant temp sensor... i broke the connector on mine installing my headers and duct taped it on and it would flicker going down the highway i drove like this for 3 months with no problems... good luck man...

 

that is the sensor for the gauge located in the head there is a seperate sensor for the pcm located in the waterpump housing and it could very well cause the problems he is describing.

 

If they have a core charge on them, they're not new. Summit might not have a core charge, but they probably charge a bit more for the units outright. I'd be surprised if they sold new-new ones, instead of Remy-new.

I don't see how it could be the ECM. Hardware is a work, or no work sort of thing. The software in them can't have problems like out computers, because they're built into a EPROM, not a hard drive. If it was in Limp Mode, he wouldn't be able to go like he is.

It could be the fuel pressure, but again, that can easily be attributed to the fuel filter not letting enough fuel pressure though.

As for the location, Billy is right. For the problem, this is my semi uneducated opinion: I don't think it would be causing that sort of problem. Seems more like it would still work normal, but would have less power throughout the RPMs, but he could still floor it and it not cut out.

 

unplug the maf and see if that helps, if we are trying cheap stuff first, it doesnt cost a thing to unplug it

 

Just from my own experience mine has done the same thing you are explaining. I replaced the pcm because it was showing it was bad. It ended up not being the problem so i went ahead and replaced the opti with a gm performance opti and it ended up being the worst mistake ever. I went through 3 in about 4 months. I went ahead and got the MSD upgraded opti for the car and it cost me $800 for it but i have yet to have that problem again. It might be one of your more expensive parts to buy but if you bought it from them not to long ago you might have some sort of policy for a defective part. It might be a long shot but if nothing else works you might look into it, as much of a pain as they are to change.

 

I just had this same problem. Clean the MAF and the electrical wire that plugs into it. Also change your fuel pressure regulator. What was happening to my car, as far as I can understand, is that the FPR was sending too much gas into the 2,4,6,8 cylinders causing the car to feel like it was misfiring. I changed those and so far so good. I would also change the 02 sensors and cats that couldn't hurt.

 

The FPR doesn't discriminate cylinders. The main line goes into it, and then it splits to each bank.

Litch, the MSD Opti is only $519. Or was this years and years ago when it was new?

This is a bit far off, but could the Air Temp Sensor be bad, unplugged? I don't know how the cars react with it bad or unplugged, so it's a total guess.

 

try a valve job

 

from my experience, the cat was clogged. it would hesitate and run like **** when it got hot. until it eventually died, then when it would cool down it would run again. gutted it and it was instantly fixed.

 

Update, Sorry I havent said much got busy with some home projects, I got a Fuel Pressure gauge now and will test to see what pressure I am getting at KEY on, Then I will start it up let it RUN, Record pressure Shut off and see if Pressure Drops. Will this be good to determine if I have a leaky injector. I will also CLEAN the MAF with MAF cleaner too

 

Okay got my results on the FUEL PSI,

Setting:
Last time car was ran was on 6/2 (just around the block)
Car has been sitting ever since on flat level driveway. 4 days

1: open gas tank cap to relieve pressure(Heard some hissing of air being relieved)
2: push in Schrader valve with Screw driver and Gas shot out!(Great no leaky injector???)
3: connect gauge
4: key on! PSI raised up to 10psi
5: let it sit for about 5 min
Still 10psi
6: start up psi raised to 19psi Mybook says it should be between 41-47 at key on and drop about 10psi when running.
7. Shut off Psi still at 19 and dropped while off to 10psi again.
8. Leaving gauge on over night just incase if drops any more.
also I really cant hear my pump when key it turned on..

IS IT MY Pump?? I still need to change fuel filter Should I do that first then retest?? I want to Drive again

 

all you have to do is pull your fuel filter off and blow in it, if stuff comes out the other end it is fine, otherwise you can go in to a shop and they can test your injectors and see which ones are B/O. Or you can replace the pump and see if that fixes it, you have a few things to see what your problem is but something fuel related is def the issue.

 

That's a poor method in my opinion. My old 62 jeep would run fine, and then have it's moments, I suspected the filter, blew through it, and deemed it ok. Still acted up. Rebuilt the carb, wasn't water in the gas, wasn't sediment, did a bunch of things. Decided to replace the filter, guess what, cured all my problems.

So, again, I tell you, as I did in the FIRST REPLY, replace the fuel filter lol. I even said before you tested the PSI, a clogged filter will cause your PSI to not read right.

 

My mom's 2002 Monte Carlo had this exact same problem. You could creep up to any speed you wanted, but as soon as you gave it 3/4 pedal to WOT, it would hesitate, backfire, and generally run like crap.

First we replaced the fuel filter. Didn't fix anything. Then we checked the fuel pressure. It was fine.

Finally we took it to a mechanic and it turned out to be a clogged CAT. Took it to the dealer and they replaced it for free. At the time (last summer) her car only had about 60K miles on it too.