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I have a 1993 chev 1/2 ton 4x4 pu with 5.7 L engine. Recently it has lost power and is getting bad mileage (relative to before). It was running really rough and replacing the plug wires and dist. cap solved a lot of the problem but is still seems to be missing, with much less power and mileage. It has had a new fuel filter, also. Cat converter has checked out as well as the dist shaft. I haven't done a compression test yet. Any obvious suggestions?

Thanks, Tom

Submitted: 61 days and 18 hours ago.

Category: Chevy

Value: $18

Status: AWAITING EXPERT REPLY

Year: 1993
Make : Chevrolet
Model: silverado
Engine: 5.7 L

Already Tried:
New plug wires, new dist cap, check Cat Converter (okay), new fuel filter, new air filter, previously had diagnostics run by mechanic (although he didn't even detect the bad plug wires!), normal service (oil change with all checks)

Posted by Tracer 61 days and 12 hours ago.

Info Request

Hello, do you feel like th engine is dropping one or 2 cylinders, kind of steady shake to engine?

61 days and 10 hours ago.

Reply

Not a steady drop in one cylinder, I have experience with that. It just idles rough, sounds rough, kind of like there is water in the gas, fouled plugs or something. Sometimes it lopes a bit at idle, but not consistently, feels like it bogs down on acceleration, have to shift down on road hills (freeway) that I used to be able to maintain speed on in overdrive. Gas is clean, many tanks through it over the last year with problems, checked by two different mechanics. It still seems electrical to me, but not as bad as when the plug wires were bad.

Posted by Tracer 61 days and 10 hours ago.

Info Request

I would love to know fule pressure. Unsure if you ahve done that yet. With a TBI fule injection, a cacuum leak, if one, would cause high idel not low/loping so we can pretty much rule that out. I am just wondering if maybe a drop in fule pressure or one of the injectors is not operating correctly. Be sure your EGR valve is not partially stuck open. May want to tap on it or pull it for pintle inspect. I will need to step out for awhile. Let me think abou this and get back with you. LMK if you come upo with anything mentioned

61 days and 9 hours ago.

Reply

We had checked the fuel pressure (had thought it poss was a fuel pump problem) and that wasn't the case. I had pretty much ruled out everything but poss compression problems (valve, etc.) or injector problems. Not sure how to check injectors. I would take it in to a good garage if I knew of one! I plan on starting over tomorrow with, electrical, plugs, compression, injecttion.... Was hoping that there was something simple I had overlooked and which didn't show up with the previous mechanics. It just doesn't seem like it should be that hard.

Answer

Well, as you know there are various sensors that only for me to view a scanner can confirm they are all ok, yes, ac ompression test is very good idea. I can not think of a simple suggest other than EGR, fuel pressure or have injectors flushed.

Accepts:
Expert:	Tracer
Pos. Feedback:	99.2 %
Answered:	9/23/2009

ASE Certified Technician

ASE Master, 32 years, All makes models foreign/dom trucks and cars

61 days and 6 hours ago.

Reply

I can't in good faith pay for the same information I have been getting from previous mechanics and other internet sights. Thanks anyway, but I am still in the same boat. I will have to decline.
Tom

Posted by Tracer 61 days and 4 hours ago.

Info Request

Ok, i understand. I just canot help or suggest more without compression readings and fuel pressure reading , Sorry. I will opt out

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Info Request

Hello, do you feel like th engine is dropping one or 2 cylinders, kind of steady shake to engine?

Reply

Info Request

Reply

Answer

Well, as you know there are various sensors that only for me to view a scanner can confirm they are all ok, yes, ac ompression test is very good idea. I can not think of a simple suggest other than EGR, fuel pressure or have injectors flushed.

Reply

I can't in good faith pay for the same information I have been getting from previous mechanics and other internet sights. Thanks anyway, but I am still in the same boat. I will have to decline. Tom

Info Request

Ok, i understand. I just canot help or suggest more without compression readings and fuel pressure reading , Sorry. I will opt out

Related Chevy Questions

I can't in good faith pay for the same information I have been getting from previous mechanics and other internet sights. Thanks anyway, but I am still in the same boat. I will have to decline.
Tom