OK my truck was running great before when I had the gastank full of Methyl Hydrate and gasoline, now thats all burned off and its got regular gas in it, its back to the same old problem I had before.

When the motor is cold, it runs great. When its hot and I slow down for a light it loses brake vacuum and runs like a wild cammed big block, so I have to touch the gas pedal and brake to get my vacuum back. I have no engine codes when this happens. It will stall if you dont click it into neuttral or touch the gas. It will run just fine with a minor intermittent shake when parked idling. It starts in one flick of the key everytime.

Ive tried cleaning all the sensors and it didnt help.

I noticed when backing into my parking spot with the door open that the exhaust stinks like rotten eggs when its doing this rough running thing...

Will a plugged catalytic convertor make it run like crap at idle speeds when driving? I cant remove the cat here cause of the aircare program we have, so I might have to cut it out and weld in a new one.

 

Im pretty sure this is my problem, the C-C is a little banged up on the outside of the casing and the exhaust stinks like rotten eggs alot of the time, its losing power and stalling alot now. Rockauto.com is selling this one for 82.79 plus shipping, is this a good deal or do any of you know a cheaper place to get it? Ive used rockauto before for berrings cause they were sooooo cheap and got Timken brand berrings in the mail which are very good.

WALKER Part # 15042 {***No Longer Legal for Use in California***; Universal (Adapters may be needed) - Inlet/Outlet I.D. 2 1/2" - O.A.L.18"}
2 WHEEL DRIVE; 4 WHEEL DRIVE; Exc. Typhoon; Modifications and/or additional parts required

Whats required to change it, is it just bolted on?
Has anyone bought a new CC and know if thats the correct part number?
Can I cut out the buggered one and put a peice of pipe in there until my new one shows up?

 

I think your exhaust is 21/4 but don't hold ne to it. Sounds like a pretty good price to me if it's a direct replacement. Warning though. I bought a direct replacement Walker cat when mine wouldn't pass NOx and it wasn't even close. My advice is to find a good muffler guy and see what they would sell you one for. That's what I did. The guy sold me a new cat and cut the flange off of mine and rewelded it on the new one. Fit perfectly. $100.00 I pulled it and reinsralled it for that price though.

 

Its giving me code 32 now only... And consistently.

 

This is an EGR fault that's for sure. There is a troubleshooting matrix in the Driveability and Emissions manual and I was thinking about summarizing it and posting it but it probably wouldn't make any sense by the time I was done butchering it. I can't scan it (scanner on the fritz) and the stuff is copywrited anyway. The first thing it tells you do do is pur a Tech 1 scan tool on it. I know this would work on your truck because it's in the 94 manual and the chart was written in 1992. If you want me to try and get it across let me know and I'll give it a stab.
To see if you have a bad EGR valve here is one of the tests. Digital volt meter required. These are resistance values. This is performed on the valve. Looks like you have to remove it first.
Terminal A - E 9.5 - 10.0 Ohms
Terminal B - D Above 3K (3000 Ohms)
Terminal B - C From .7 to 4.0K (4000) Ohms while slowly moving pintle valve inward

 

Yeah any help you can give would be just great. Im down in the US today, but I will test that stuff tomorrow when I hump it home, not very far, Im just across the border, and I live on the other side. I also have an EGR valve from the junkyard thats in nice shape in case.

 

OK man. Here it goes. A little info you need to know about the wiring to the EGR valve and the PCM. You have 5 wires in the connector to the EGR valve and come (or go) to the PCM with one tapped into the fuse block. We will be refering back these circuits so here they are. Ckt = circuit
Ckt 435 Gry wire from PCM terminal E1 (EGR control) to EGR terminal A
Ckt 455 Ppl wire from PCM terminal B4 (sensor ground) to EGR terminal B
Ckt 1456 Brn wire from PCM terminal B16 (pintle position signal) to EGR terminal C
Ckt 474 Gry wire from PCM terminal E14 (5 volt reference) to EGR terminal D
Ckt 39 Pnk/Blk wire from PCM terminal F15 (ignition feed) to EGR terminal E. This is also spliced into by the Pnk/Blk wire from Fuse #4 (Gauges - 20 amp) and from there to the ignition switch.
The manual tells you to put a Tech 1 scan tool on the truck, run it at 1500 rpm and command the EGR valve to 25%. Did actual EGR position go to 25%?
A.1. If Yes then check EGR and passages for blockage. If OK DTC 32 is intermittent and go to "Dianostic Aids" (which is the test I put in the last post)
A.2. If No (here we go!) is actual EGR position 0%?
A.2.a. If No check resistance from EGR terminal A to E. Resistance should be 7.8 - 8.6 Ohms.
A.2.a.1. If resistance is out of these parameters replace EGR valve
A.2.a.2. If Yes Ckt 435 grounded or faulty PCM. Refer to Diagnostic Aids
A.3. With EGR commanded to 25% did the EGR duty cycle go to 100%
A.3.a. If No Disconnect EGR harness connector. Probe Ckt 455 with test light connected to 12v. Is test light on?
A.3.a.1. If No Ckt 455 open or faulty PCM. Refer to Diagnostic Aids
A.3.a.2. If Yes check Ckt 1456 for voltage with digital meter. Should be .5 volts
A.3.a.2.(a). If Less than .5 volts - faulty EGR valve
A.3.a.2.(b). If More than .5 volts - repair short to voltage on Ckt 1456
A.3.b. If Yes (duty cycle to 100%) disconnect EGR connector, key on, engine off - with test light connected to ground probe terminal E of EGR connector.
A.3.b.1. Light off repair open or short to ground in Ckt 39
A.3.b.2. Light on - Connect test light between EGR harness connector terminals A & E and ground diagnostic terminal.
A.3.b.2.(a). Light off - Open Ckt 435 or faulty PCM. Refer to Diagnostic Aids
A.3.b.2.(b). Light on - remove EGR valve and connect digital meter across Ckt 1456 and Ckt 455. [There is a typo in the manual here. I think this is correct but could be Ckt 474 instead of 455] Slowly push on the pintle valve. Resistance should change from .70 to 4.0K Ohms
A.3.b.3.(a). If No replace EGR valve
A.3.b.3.(b). If Yes open or shorted Ckt 1456 or faulty PCM. Refer to Diagnostic Aids

You owe me big time brother. But that's it for checking the EGR valve. If you need clarification on anything just ask. Most of it you can do and not have a scan tool to drive the valve to 25% I would think. But if you have one it would be a whole lot better.

 

quick question, if you put the egr valve on but don't plug it in will it throw a code?

 

I would think that it would since the circuits now have opens in them. Don't know for sure though. I accidently disconnected one of my knock sensors once and it threw a code immediately so I imagine it would on this too.

 

Ok thanks gimpy sorry for stealing the thread lol I just recently replaced my egr valve with one from a 2000 trans am as my friend is turboing his car and no longer needs that. It's the exact same but the plug is not l shaped and I had to wedge the connector in there because the bracket for the alt tensioner was in the way and wast too shure it was in there all the way