I've run into an interesting issue. While I am able to get my car to idle smoothly when I drive it it sputters and about dies unless I keep out of the gas pedal. When I touch the pedal it sputters and sounds like it threw a rod bearing (detonation?). I'm stumped to the point I am ready to throw and engine at this thing. An idears?

 

It's not an engine problem, it's an engine CONTROLS problem. Nobody can help without a year and what, if anything, has been done so far.

 

OH no. I pulled a noob move.

Okay, it is a 1990 3.1l Firebird. I recently replaced the starter, alternator and fuel pump (it had been sitting for 5 years with a bad fuel pump). Along with new catback too.

Next I am going to clean the throttle body. Not sure what else around there I should clean as well.

 

Did you replace the fuel filter yet? Also do a full tune up and get some new basic parts in there before you go digging any deeper. Keep in mind that with the car having sat so long without running, you may be looking at new valve cover gaskets as well.

 

I've just realized there was more that I did do. Sorry, this has been a project I am just getting back to after a couple months.

Fuel Filter, ignition coil, ignition control module, oil/filter, catalytic convertor. I think that was all.

I am sure the valve colver gaskets will be next on the list, Maybe I should grab some plugs on the way home today along with carb cleaner.

What about eh TPS, is there a way I can check it?

 

The problem you're having sounds like the engine is leaning out... The filter baskets in the inlet end of the injectors may be gummed up... Send them to be cleaned or replace them. At the same time, remove the fuel lines from the fuel rail (VERY carefully as they cross-thread easily and like to leak), and blow them out with a blow gun on an air compressor. Might want to disconnect the fuel filter end of the pressure line first. You will need to get a pair of fuel line o-rings if you choose to do this.

I bought a 2.8 fuel rail someone on here had sitting on a shelf forever. Put it on my engine and the fuel pressure, which HAD been 43 PSI sitting pretty, shot up to 60+... Return side was plugged. Only mentioning this because the same may have happened in one of your fuel lines. Also check for leaks, of course.

 

I found my problem!!!! After checking and rechecking things I noticed a hardline vacuum hose that was a bit melty and had a hole in it. I then noticed that the brake booster vacuum hose was about to fall off and realized how loose it was. I cut the ends down (it was plenty long) and cut and rerouted the melted hardline away from anything hot. Started up the car and took it on a test drive down the block!!!!

All i need to do is get it registered and insurance so I can take it on a bit longer drive. I had my son hop in and we drove to the opposite end of the block. The car may eventually be his.

Thank you for all the suggestions Maverick!

 

Well I ended up pulling the injectors out and checking them all because it started running poorly again, also blew out the fuel lines. Reassembled it all did the idle relearn and she is running.

It stalls at wide open throttle. Keep in mind new fuel pump, and filter. Could it be an issue with the fuel pressure regulator? I have chased and fixed some vacuum leaks as well.

It will run fine as long as I keep my foot out of it, heck I was cruising along at 70 and the car was running fine, I gave it WOT the RPM's went up and then came crashing down. It took about 30 seconds to recover from that then it was back to normal. But I was still not able to do any WOT anytime or quick throttle changes from a stop.

 

Either the fuel pump can't maintain fuel pressure, or the injectors are shorting out and the ECM can't drive them. Check the resistance of the injectors, they must be around 12 ohms each.

RBob.

 

RBob, I had the injectors out last week and checked the resistance on all of them and they were within spec. I'm more concerned that the pump can't maintain pressure, but it has less that an hour on it. That is why I was thinking fuel pressure regulator. I am a bit stumped on this one. I need to get a fuel pressure gauge.

 

When you get a gauge, try to rig it up so you can watch it while driving. See if the pressure is dropping when you go WOT.

If the pressure checks out, it's possible the injectors are shorting as they heat up. They sometimes test good when cold but get worse with heat. I've seen that demonstrated in some videos from a shop that refurbs injectors.
It's also possible they could be physically clogged. That's not uncommon with a car that's been sitting.